Restricting __malloc_hook to a particular library - c++

Question

I am trying to use __malloc_hook in our code to manage memory. But It is impacting to client code as well where I don't want to manage memory.
Below is the sample code. :
mathtest.h
int addNumbers(int x, int y);
int subNumbers(int x, int y);
addNumbers.cpp
#include <cstdlib>
#include <iostream>
#include <malloc.h>
using namespace std;
static void my_init_hook (void);
static void *my_malloc_hook (size_t, const void *);
//static void my_free_hook (void*, const void *);
/* Variables to save original hooks */
static void *(*old_malloc_hook)(size_t, const void *);
static void
my_init_hook (void)
{
old_malloc_hook = __malloc_hook;
//old_free_hook = __free_hook;
__malloc_hook = my_malloc_hook;
//__free_hook = my_free_hook;
}
static void *
my_malloc_hook (size_t size, const void *caller)
{
void *result;
/* Restore all old hooks */
__malloc_hook = old_malloc_hook;
// __free_hook = old_free_hook;
/* Call recursively */
result = malloc (size);
/* Save underlying hooks */
old_malloc_hook = __malloc_hook;
//old_free_hook = __free_hook;
/* printf might call malloc, so protect it too. */
printf ("malloc (%u) returns %p\n", (unsigned int) size, result);
/* Restore our own hooks */
__malloc_hook = my_malloc_hook;
//__free_hook = my_free_hook;
return result;
}
int addNumbers(int x, int y)
{
my_init_hook();
int *p = (int*)malloc (100);
cout<<"memory in add numbers : "<<p<<endl;
return x+y;
}
subNumbers.cpp
#include <iostream>
#include <malloc.h>
#include <cstdlib>
using namespace std;
int subNumbers(int x, int y)
{
int *p = (int*)malloc (100);
cout<<"memory in sub numbers : "<<p<<endl;
return x-y;
}
doMath.cpp (Client code)
#include <time.h>
#include <iostream>
#include <cstdlib>
#include "mathtest.h"
using namespace std;
int main()
{
time_t t;
srand((unsigned) time(&t));
int rNuma = rand();
int rNumb = rand();
int answer;
answer = addNumbers(rNuma, rNumb);
cout<<"add = "<<answer<<endl;
answer = subNumbers(rNuma, rNumb);
cout<<"Subtract = "<<answer<<endl;
int *p = (int*)malloc(20000);
cout<<"malloc address in domath : "<<p;
return 0;
}
Header are inside include folder and SO will be kept inside lib folder.
Below are the steps to compile.
g++ -fpic -c addNumbers.cpp subNumbers.cpp
g++ -o libmath.so.1.3.0 addNumbers.o subNumbers.o -fpic -shared -Wl,-soname,libMath.so.1
create soft link
g++ doMath.cpp -o doMath -lMath -I include -L lib
./doMath
Below is the output:
malloc (100) returns 0x564b23f6ee70
memory in add numbers : 0x564b23f6ee70
add = 1549862266
malloc (100) returns 0x564b23f6f2f0
memory in sub numbers : 0x564b23f6f2f0
Subtract = 1535975764
malloc (20000) returns 0x564b23f6f360
__malloc_hook callback is getting called for client code as well. which I don't want.
One possible solution is to reset __malloc_hook callback before calling malloc in client code. But this solution would not work if client code is running on separate thread.
Any possible solution where We can restrict the __malloc_hook so that It doesn't affect the client code. Any help would be much appreciated. Thanks in Advance.